Throwable objects.
+ *
+ * @author Daniel Rall
+ * @since 1.0
+ */
+public class ExceptionUtils
+{
+ /**
+ * The name of the getCause() method.
+ */
+ protected static final String CAUSE_METHOD_NAME = "getCause";
+
+ /**
+ * The parameters of the getCause() method.
+ */
+ protected static final Object[] CAUSE_METHOD_PARAMS = {};
+
+ /**
+ * Constructs a new ExceptionUtils. Protected to
+ * discourage instantiation.
+ */
+ protected ExceptionUtils()
+ {
+ }
+
+ /**
+ * Introspects the specified Throwable for a
+ * getCause() method (standard as of JDK 1.4, and
+ * part of the {@link
+ * org.apache.commons.lang.exception.NestableException} API),
+ * extracting and returning the cause of the exception.
+ * Otherwise, returns null.
+ *
+ * TODO: Examine for a "detail" public member attribute from
+ * java.rmi.RemoteException.
+ *
+ * @param t The exception to introspect for a cause.
+ * @return The cause of the Throwable.
+ */
+ public static Throwable getCause(Throwable t)
+ {
+ Throwable cause = null;
+
+ if (t instanceof NestableException)
+ {
+ cause = ((NestableException) t).getCause();
+ }
+ else if (t instanceof NestableRuntimeException)
+ {
+ cause = ((NestableRuntimeException) t).getCause();
+ }
+ else
+ {
+ Method getCause = null;
+ Class c = t.getClass();
+ try
+ {
+ getCause = c.getMethod(CAUSE_METHOD_NAME, null);
+ }
+ catch (NoSuchMethodException ignored)
+ {
+ }
+ catch (SecurityException ignored)
+ {
+ }
+
+ if (getCause != null && getCause.getReturnType() == Throwable.class)
+ {
+ try
+ {
+ cause = (Throwable) getCause.invoke(t, CAUSE_METHOD_PARAMS);
+ }
+ catch (IllegalAccessException ignored)
+ {
+ }
+ catch (IllegalArgumentException ignored)
+ {
+ }
+ catch (InvocationTargetException ignored)
+ {
+ }
+ }
+ }
+
+ return cause;
+ }
+
+ /**
+ * Walks through the exception chain to the last element -- the
+ * "root" of the tree -- using {@link #getCause(Throwable)}, and
+ * returns that exception.
+ *
+ * @return The root cause of the Throwable.
+ * @see #getCause(Throwable)
+ */
+ public static Throwable getRootCause(Throwable t)
+ {
+ Throwable cause = getCause(t);
+ if (cause != null)
+ {
+ t = cause;
+ while ((t = getCause(t)) != null)
+ {
+ cause = t;
+ }
+ }
+ return cause;
+ }
+}
diff --git a/src/test/org/apache/commons/lang/exception/ExceptionTestSuite.java b/src/test/org/apache/commons/lang/exception/ExceptionTestSuite.java
index 56ceaa8a6..294172a3a 100644
--- a/src/test/org/apache/commons/lang/exception/ExceptionTestSuite.java
+++ b/src/test/org/apache/commons/lang/exception/ExceptionTestSuite.java
@@ -88,6 +88,7 @@ public class ExceptionTestSuite extends TestCase
suite.addTest(NestableDelegateTestCase.suite());
suite.addTest(NestableExceptionTestCase.suite());
suite.addTest(NestableRuntimeExceptionTestCase.suite());
+ suite.addTest(ExceptionUtilsTestCase.suite());
return suite;
}
}
diff --git a/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java b/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
new file mode 100644
index 000000000..4dcff4156
--- /dev/null
+++ b/src/test/org/apache/commons/lang/exception/ExceptionUtilsTestCase.java
@@ -0,0 +1,128 @@
+package org.apache.commons.lang.exception;
+
+/* ====================================================================
+ * The Apache Software License, Version 1.1
+ *
+ * Copyright (c) 2002 The Apache Software Foundation. All rights
+ * reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. The end-user documentation included with the redistribution, if
+ * any, must include the following acknowlegement:
+ * "This product includes software developed by the
+ * Apache Software Foundation (http://www.apache.org/)."
+ * Alternately, this acknowlegement may appear in the software itself,
+ * if and wherever such third-party acknowlegements normally appear.
+ *
+ * 4. The names "The Jakarta Project", "Commons", and "Apache Software
+ * Foundation" must not be used to endorse or promote products derived
+ * from this software without prior written permission. For written
+ * permission, please contact apache@apache.org.
+ *
+ * 5. Products derived from this software may not be called "Apache"
+ * nor may "Apache" appear in their names without prior written
+ * permission of the Apache Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
+ * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation. For more
+ * information on the Apache Software Foundation, please see
+ *